1. Field of the Invention
The present invention relates to technology of treatment of polluted water. More particularly, this invention relates to an apparatus for purifying polluted water that can remove polluted water that has not yet been discharged from a treatment tank.
2. Description of the Related Art
In general, polluted materials are classified into point source pollutants and non-point source pollutants according to their pollution source (point pollution source and non-point pollution source). The non-point pollution source refers to a source that generates pollutants without any particular discharging paths, such as dusts from vehicle exhaust and tires, etc., which collect on roads, bridges, or parking lots, or in harmful dregs that build up on golf course grounds, farmland, and on construction sites, etc. When such pollutants are washed into rivers along with rainwater, water pollution occurs. Since these non-point source pollutants are washed into the rivers by rainwater, they are mixed with a variety of polluted materials that have various physical and chemical properties. To effectively purify such polluted water, the variety of polluted materials mixed and included in the polluted water must be sorted in stages, using their respective physical and chemical properties. In each stage, a polluted-water purification device is installed to comply with the types of polluted materials intended to be sorted.
For example, a hydraulic separation device serves to precipitate, float, sort, and separate suspended solid, and nutrient, and oil, etc., using a specific gravity difference and a density difference.
This hydraulic separation device is configured in such a way to receive polluted water through an inlet, separate and filter the polluted water in a treatment tank, and discharge the treated water through an outlet. The outlet is formed at a certain height from the bottom of the treatment tank such that the polluted water can be treated and then discharged from the treatment tank. That is, the treatment tank cannot discharge the polluted water under the point at which the outlet is installed. Therefore, the polluted water under the outlet becomes stagnant in the treatment tank and then decays, causing odor. Such an environment is conducive to insect infestation.
In a conventional art, a pump car must be employed to remove settled polluted materials in the treatment tank. Since the pump car pumps out stagnant polluted water as well as polluted materials, it can only remove a relatively small amount of polluted material from the treatment tank. That is, the conventional pump car has a limitation in that it can only effectively pump the polluted materials once, which causes high maintenance fees to maintain the treatment tank.